Transcript Unit 6:11 Digestive System

Chapter 7:11
Digestive System
Objectives
 Label the major organs of the digestive system
 Identify at least three organs on a diagram of the
digestive system
 Cite two functions of the salivary glands
 Describe how the gastric juices act on food in the
stomach
 Explain how food is absorbed into the body by the villi in
the small intestine
 List at least three functions of the large intestine
 List at least four functions of the liver
 Explain how the pancreas helps digest foods
 Describe at least five diseases of the digestive system
 Define, pronounce, and spell all the key terms
Digestive System
Gastrointestinal System
 Responsible for the physical and chemical
breakdown of food so that it can be taken into
the bloodstream and used by body cells and
tissues
 Alimentary Canal- long, muscular tube that
begins at the mouth and includes the mouth,
pharynx, esophagus, stomach, small intestine,
large intestine, and anus
 Accessory organs- salivary glands, tongue,
teeth, liver, gallbladder, and pancreas
Parts of the Alimentary Canal
 Mouth
 “buccal cavity”
 Receives food as it
enters the body
 Food is tasted,
broken down
physically by the
teeth; lubricated and
partially digested by
saliva; and swallowed
Parts of the Alimentary Canal
 Teeth
 Physically break
down food by
chewing and grinding
(Mastication)
Parts of the Alimentary Canal
 Tongue
 Muscular organ
 Contains special
receptors called taste
buds
 Allows a person to
taste sweet, salt,
sour, and bitter
sensations
 Aids in chewing and
swallowing food
Parts of the Alimentary Canal
 Hard palate
 Bony structure that
forms the roof of the
mouth
 Separates the mouth
from the nasal
cavities
Parts of the Alimentary Canal
 Soft Palate
 Behind the hard
palate
 Separates mouth
from the nasopharynx
 Uvula- hangs from the
middle of soft palate
-prevents food from
entering the
nasopharynx during
swallowing
Parts of the Alimentary Canal


Salivary Glands
Three pairs
 Saliva
-lubricates mouth during
speech and chewing
-moistens food so that it
can be swallowed easily
 Salivary amylase
 Enzyme that speeds up a
chemical reaction
 Formerly known as
ptyalin
 Begins the chemical
breakdown of
carbohydrates, or
starches, into sugars that
can be taken into the
body
Parts of the Alimentary Canal
 Pharynx
 “throat”
 Tube that carries both
air and food
 Carries air to trachea
 Carries food to
esophagus
Parts of the Alimentary Canal
 Esophagus
 Muscular tube dorsal to
the trachea
 Receives the bolus
(chewed food mixed with
saliva) and carries it to
the stomach
 Relies on rhythmic,
wavelike, involuntary
movement of its muscles,
called peristalsis, to move
food in a forward direction
Parts of the Alimentary Canal
 Stomach
 Enlarged part of
alimentary canal
 Receives food from the
esophagus
 Contains folds called
rugae
 Food usually remains in
the stomach approx. 1 -4
hours
 Chyme- semifluid
material that the food is
converted into during this
time in the stomach
Parts of the Alimentary Canal
Gastric juices
Produced by glands in the stomach
Contain:
-hydrochloric acid – kills bacteria, facilitates
iron absorption, and activates the enzyme
pepsin
Parts of the Alimentary Canal
Enzymes in the gastric juices
Lipase- starts chemical breakdown of fats
Pepsin- starts protein digestion
Rennin (in infants) secreted to aid in the
digestion of milk
Rennin is not present in adults
Parts of the Alimentary Canal


Small intestine
Coiled section of
alimentary canal
 Approx. 20 feet in length
and one inch in diameter
 Divided into three
sections
1. Duodenum- first 9 – 10
inches
Bile-(from gallbladder and
liver)
Pancreatic juice- enters
the duodenum through
ducts
Small Intestine
2. Jejunum
 Approx. eight feet in
length
 Forms the middle
section
Small Intestine
3.



Ileum
Final 12 feet
Connects with the large intestine at the cecum
Ileocecal valve- separates the ileum and
cecum
-prevents food from returning to the ileum
-digestion is completed in the small intestine
-products of digestion are absorbed into the
bloodstream for use by the body cells
Intestinal juices produced by the small
intestine
 Contains enzymes:
-maltase
-sucrase
-lactase
-peptidases- complete the
digestion of proteins
-steapsin- aids in digestion
of fat
-Bile- emulsifies fats
 Pancreatic juices
 Complete the process of
digestion
 Enzymes:
-pancreatic amylase or
amylopsin- acts on
sugars
-trypsin and chymotrypsinact on proteins
-lipase or steapsin- act on
fats
Small intestine
 Villi- fingerlike projections that line the small
intestine
 Contain blood capillaries and lacteals
 Capillaries absorb the digested nutrients and
carry them to the liver, where they are stored or
released into general circulation for use by the
body cells
Large Intestine
 Final section of the alimentary
canal
 Approx five feet in length and
two inches in diameter
 Functions:
-absorb water and any remaining
nutrients
-storage of indigestible materials
before they are eliminated from
the body
-synthesis and absorption of some
B-complex vitamins and vitamin
K by bacteria present in the
intestine
-transportation of waste materials
out of the alimentary canal
Large Intestine
 Divided into a series
of connected
sections
1. Cecum- first section
-Connected to the
ileum
-contains vermiform
appendix
Large Intestine
2. Colon
 Several divisions
Ascending colon
-continues up on the right
side of the body
-from cecum to the lower
part of the liver
Transverse Colon
-extends across the
abdomen
-below the liver and
stomach
-above the small intestine
Large Intestine
Descending Colon
-extends down the left
side of the body
-connects with the
sigmoid colon
Sigmoid colon
-an S-shaped section
-joins with the rectum
Large Intestine
Rectum
-final 6 – 8 inches
-storage area for
indigestibles and wastes
-anal canal- narrow canal
which opens at the anus
-fecal material, or stool, the
final waste product of the
digestive process, is
expelled through this
opening
Accessory Organs
 Liver
 Largest gland in the body
 In the RUQ of the
abdomen
 Secretes bile
 Stores sugar in the form
of glycogen
 Glycogen-converted to
glucose and released into
to the bloodstream when
additional blood sugar is
needed
Liver
 Stores iron and certain
vitamins
 Produces:
 Heparin
 Blood proteins
 Cholesterol
 Liver detoxifies
substances like alcohol
and pesticides
 Destroys bacteria that
have been taken into the
blood from the intestine
Gallbladder
 Small, muscular sac
 Located under the
liver and attached to it
by connective tissue
 Stores and
concentrates bile
Pancreas
 Glandular organ
 Located behind the
stomach
 Produces pancreatic
juices
 Also produces insulin
 Insulin
-secreted into bloodstream
-regulates the metabolism,
or burning, of
carbohydrates to convert
glucose to energy
Diseases and Abnormal Conditions
 Appendicitis
 Acute inflammation of the appendix
 Usually resulting from an obstruction and
infection
 Symptoms:
-generalized abdominal pain (later localizes in
RLQ)
-nausea/vomiting
-mild fever
-elevated WBC count
 Treatment:
 Appendectomy
Diseases and Abnormal Conditions
 Cholecystitis
 Inflammation of the gallbladder
 Cholelitiasis- when gallstones form
 Symptoms:
-occur after eating fatty foods
-indigestion
-nausea/vomiting
-pain that starts under the rib cage and radiates to the
right shoulder
 Treatment:
-low-fat diet
-lithotripsy
-cholecystectomy
Diseases and Abnormal Conditions
 Cirrhosis
 Chronic destruction of liver cells accompanied
by the formation of fibrous connective and scar
tissue
 Causes:
-hepatitis
-bile duct disease
-chemical toxins
-malnutrition associated with alcoholism
Cirrhosis
 Symptoms:
-vary and become more
sever as the disease
progresses
-hepatomegaly
-anemia
-indigestion
-nausea/vomiting
-nosebleeds
-jaundice
-ascites
Cirrhosis
 When the liver fails:
-disorientation
-hallucinations
-hepatic coma
-death
 Treatment:
-directed at preventing further damage to the liver
-alcohol avoidance
-proper nutrition
-vitamin supplements
-rest
-infection prevention
-appropriate exercise encouraged
Constipation
 When fecal material remains in the colon too
long, causing excessive reabsorption of water
 Feces becomes hard, dry
 Causes: poor bowel habits, chronic laxative use
leading to “lazy” bowel, diet low in fiber, certain
digestive diseases
 Treatment: high fiber diet, adequate fluids,
exercise
Diarrhea
 Condition characterized by frequent watery
stools
 Causes:
-infection
-irritated colon
-toxic substances
 Treatment:
-directed toward eliminating the cause
-providing adequate fluid intake
-modifying the diet
Diverticulitis
Diverticulitis
 Inflammation of the diverticula that form in the intestine
(the mucosal lining pushes through the surrounding
muscle)
 When fecal material and bacteria become trapped
 Symptoms:
-vary depending on the amount of inflammation
-abdominal pain
-irregular bowel habits
-flatus
-constipation or diarrhea
-abdominal distention
-fever
-nausea/vomiting
Diverticulitis
Treatment:
-antibiotics
-stool softeners
-pain medications
-surgery to remove the affected area of the
colon in severe cases
Gastroenteritis
 Inflammation of the mucous membrane that lines
the stomach and intestinal tract
 Causes: food poisoning, infections, toxins
 Symptoms: abdominal cramping, nausea and
vomiting, fever, diarrhea
 Treatment: rest, increased fluid intake,
antibiotics (in severe cases), intravenous fluids
(Ivs), medications to slow peristalsis
Hemorrhoids
 Painful, dilated, or
varicose veins of the
rectum and/or anus
 Causes:
-straining to defecate
-constipation
-pregnancy
-insufficient fluid intake
-laxative abuse
-prolonged sitting or
standing
Hepatitis
Viral inflammation of the liver
Type A, HAV
-infectious hepatitis
-highly contagious
-transmitted by the feces on an infected
person
Vaccine is available to prevent Hep A
Hepatitis
Type B, HBV (serum hepatitis)
-transmitted by blood and serum
-more serious than Type A
-can lead to chronic hepatitis or to cirrhosis
of the liver
Vaccine developed to prevent Hep B is
recommended for all health care workers
Hepatitis
 Other strains have been identified:
 Types C, D, and E
 Symptoms:
-fever
-anorexia
-nausea/vomiting
-fatigue
-dark colored urine
-clay-colored stools
-hepatomegaly
-jaundice
Hepatitis
Treatment:
-rest
-diet high in protein and calories low in fat
-Liver transplant may be necessary if the
liver is severely damaged
Hernia
“rupture”
When an internal organ pushes through a
weakened area or natural opening in a
body wall
Hiatal hernia- when the stomach protrudes
through the diaphragm and into the chest
cavity through the opening for the
esophagus
Hernia
Symptoms:
-heartburn
-stomach distention
-chest pain
-difficult swallowing (dysphagia)
Treatment:
-bland diet
-small frequent meals,
-staying upright after eating
-surgical repair (herniorrhaphy)
Hernia
Pancreatitis
 Inflammation of the pancreas
 Pancreatic enzyme begins to digest the
pancreas itself, pancreas becomes necrotic,
inflamed, and edematous
 Causes: excessive alcohol consumption, injury,
blockage of the ducts by gallstones, idiopathic
Pancreatitis
Symptoms: severe abdominal pain that
radiates to the back, nausea and vomiting,
diaphoresis, jaundice
Treatment:
-depends on the cause
-cholecystectomy if gallstones are the cause
-analgesics
-nutritional support
-poor prognosis
-often results in death
Pancreatitis
Treatment:
-depends on the cause
-cholecystectomy if gallstones are the
cause
-analgesics
-nutritional support
-poor prognosis
-often results in death
Peritonitis
 Inflammation of the abdominal peritoneal cavity
 Usually occurs when a rupture in the intestine
allows the intestinal contents to enter the cavity
 Symptoms:
-abdominal pain and distention
-fever
-nausea/vomiting
 Treatment: antibiotics, surgical repair of the
damaged intestines
Ulcer
 An open sore on the
lining of the digestive
tract
 Peptic ulcers
 Major cause:
Helicobacter pylori
(H.Pylori)
-causes burrowing into
the stomach
membranes
Ulcers
 Symptoms: burning pain, indigestion, hematemesis,
melena
 Treatment:
-antacids and pepto bismol
-bland diet
-decreased stress
-avoidance of irritants (alcohol, tobacco, fried foods, and
caffeine
-Antibiotics
-surgery in severe cases
Ulcerative Colitis
Severe inflammation of the colon
accompanied by the formation of ulcers
and abscesses
Causes:
-thought to be by stress, food allergy, or
autoimmune reaction
Main symptom: diarrhea
Ulcerative Colitis
Other Symptoms:
-weight loss
-weakness
-abdominal pain
-anemia
-anorexia
Periods of remission and exacerbation are
common
Ulcerative Colitis
 Treatment:
-directed toward controlling
inflammation
-maintaining proper
nutrition
-avoiding substances that
aggravate the condition
-surgical removal of the
affected colon and
creation of a colostomy